IPS transformation doesn't remove users from group when information changes

[#1]

In IPS I've added to the target transformation to add users to a group based on a regex.

Users are not removed from the group if they no longer match the regex if the regex is updated.  How do I keep the groups updated?

SAP Cloud Identity Services Identity Provisioning 

This is the transformation that adds users to the group

{
"targetPath": "$.groups[0].value",
"condition": "($.emails[0].value =~ /^(([email protected]).)*$/)",
"constant": "myGroupName"
}